The asteroid Pallas was discovered March 28, 1802 in Bremen by the German astronomer Heinrich Wilhelm Olbers (1758-1840) while he took care of observations to find and determine the orbit of the asteroid Ceres. Ceres was discovered by Giuseppe Piazzi previous year (1746/1826), using forecasts of the great mathematician Carl Friedrich Gauss (1777-1855). Many small rocky bodies called asteroids are present in the solar system, an important part of them circulate in a ring between the orbits of Mars and Jupiter between 2 and 4 AU (symbol: AU) The average distance Earth to the Sun. One AU is 149 597 871 km. It is a unit often used for distances in the solar system, or the distance between two stars in a binary system. in what astronomers call the asteroid belt, otherwise known main belt.
This belt marks the boundary between the terrestrial planets and the gas giants. Pallas is the second largest main belt asteroid with a mean diameter of 526 km and the second one was discovered. The orbit of Pallas is almost identical to that of Ceres, Ceres and Pallas have rotation periods of 4.6 years. Pallas has a high orbital inclination to the plane of the ecliptic, it is 34.8 °, while that of Ceres is 10.5 °. The object is according to U.S. researchers, a protoplanet, i.e. a body massive enough to form a planet, but frozen in its evolution by lack of matter.
An article published in Science by Britney E. Schmidt and his colleagues said that Pallas is one of the intermediate stages between planetesimal and planet. Through images provided by the Hubble one sees a large impact crater very old. The mass of Pallas represents about 7% of the total mass of the objects of the asteroid belt.
Pallas was named in honor of the Greek goddess of wisdom, science and the arts.
The name of the chemical element Palladium (46), discovered in 1803, is derived from the asteroid Pallas.
nota: The interplanetary space is far from empty, it is littered with dust and matter dating from the creation of the solar system. Asteroids are mainly located in the main belt between the orbits of Mars and Jupiter (between 300 and 600 million km from the Sun). There are hundreds of thousands of objects listed. All objects could have formed a planet in the area but the gravitational perturbations of Jupiter did not permit.
Image: With a diameter of 570 x 525 x 482 km, Pallas is the second largest known asteroid belonging to the asteroid belt between Mars and Jupiter. Pallas is not quite round, it runs on a highly inclined orbit of 34.8 °. Its orbital period is 4.6 years. With an eccentricity of 0.23, its distance varies between 2.14 AU closer to the Sun and 3.41 AU away. High resolution images of the Hubble Space Telescope, we present here a model of the asteroid Pallas.
Image: List of the largest asteroids classified by size.